Pelvic organ prolapse (“POP”) is defined as a condition in which vaginal wall support is lost, and various pelvic organs prolapse into the vagina. This is a very troublesome condition, though in most cases it is not a dangerous one. POP might appear alone or in combination with urinary stress incontinence.
Prolapse of adjacent organs into the vagina is quite common, in variable degrees. The reasons for such a prolapse are mainly damage to the endopelvic fascia which surrounds the organs and keeps them in the right position, pelvic floor muscular damage, and/or neural damage. There might also be a change within the collagen composition, thereby causing a weaker pelvic floor. According to an older classification system, prolapse may be divided into five categories depending on the organ that is sagging down (urethra, bladder, uterus, rectum and the pouch of Douglas), and into three grades according to the amount of descent (within the vagina, at the entrance to the vagina, protruding out of the vagina). There might be a combination of various organs prolapse at the same time, with different levels of descent. The newer classification (POP-Q) takes into account other factors, such as location of the prolapse and the distance from the entrance of the vagina.
Prolapse of the urethra, named urethrocele, is one of the several possibilities for pelvic organ prolapse around the vagina. The most frequent prolapse is of the bladder, named cystocele, as a result of its weight. Prolapse of posterior fornix, with bowl inside is called enterocele, and prolapse of the posterior vaginal wall with the rectum in it is termed rectocele. When the ligaments that hold the uterus in place weaken, a uterine descent occurs. In cases where the uterus has been removed, and the vagina is dome shaped, a vault prolapse may occur.
Referring now to FIG. 1A, an anatomical front view of a vagina 100 is depicted. The sidewalls have thin longitudinal and circular muscles 108, externally wrapped by a pelvic fascia 110. It has been determined that the pelvic fascia 110 tends to become weakened, stretched and attenuated over time and as a result of various stresses, such as childbirth. Such weakening of the pelvic fascia allows for sagging and thus, prolapses of different pelvic organs into and through the vagina 100. The inside circumference of the vagina 100 is covered with mucosa 106.
The vaginal cavity is almost always deformed by prolapse when the anterior wall 112 collapses, or is too weak to hold. Often, the bladder's weight causes the anterior wall 112 to collapse and occlude the vaginal lumen from above. On the other hand, the posterior wall 114 can be stressed by the bowel. The conglomeration of these stresses can result in an occlusion of the vaginal lumen shaped like a letter “H”, depicted in FIG. 1B.
FIG. 1C is an illustration of the vaginal shape from a side view. It can be seen that vaginal diameters are not constant along the vaginal axis. Lateral diameter is usually shorter closer to the entrance 118, but gradually becomes longer internally 116. The same applies for the antero-posterior diameter. The vaginal diameter close to the entrance is typically shorter than the vaginal diameter behind the perineal body. As a generalization, the vagina may be looked at as a funnel shaped organ.
There are certain defined organs in direct contact with the vagina or within short proximity, as depicted in FIG. 1D. The bladder 136 is a hollow, sack-like organ, in which the urine is accumulated prior to it's expulsion outside the body through the urethra 142. The bladder is located behind the pubic bone 138 and rests on the middle third of the vagina. The urethra is a short muscular pipe, 25-35 mms in length, in direct contact with the bladder at the bladder neck 140 resting on the lower third of the anterior vaginal wall, in direct contact with the pubic bone. The uterus 130 is a pear shaped organ that has a lower part, the cervix 132 which protrudes into the dome of the vagina. The body of the uterus is an abdominal organ, which, in most cases bends forward on the bladder. The cervix, while protruding into the vagina creates 4 fornices—2 laterals which are of the same dimensions, one smaller anterior 134, and one posterior 122, which is actually behind the cervix 132. The posterior fornix has direct contact with the pouch of Douglas 120 which is the deepest part of the abdominal cavity, on top of the vagina. The posterior surface of the vagina is in contact with the rectum 124, until the area where a thick muscular body, the perineal body which is part of the pelvic floor and the sphincter of the anus 128.
At present there are two ways of dealing with Pelvic Organ Prolapse. The first method for treatment involves surgery, which can be vaginal or abdominal. Surgical intervention is typically undesirable due to cost, pain and suffering to the patient and the possibility that even surgery will fail to be effective. Efforts to avoid surgical procedures have resulted in the development of a number of non-surgical vaginal devices, inserted into the vagina by the surgeon or the patient. Therefore, the second method of treatment requires the use of vaginal devices (pessaries) that are inserted into the vagina and mechanically reduce the prolapse by pushing the vaginal walls aside and upwards. Vaginal devices are well known for their tremendous diversity in shapes and sizes.
Some of these devices tend to block all flow of urine from the bladder. Therefore, when a patient needs to urinate, the device must be removed from the vagina or must be collapsed to remove the pressure applied against the bladder neck. Trying to solve this problem, vaginal devices were developed in special shapes that do not completely block the bladder neck, so that the patient may urinate with the device in place. These devices, however, are generally large and intrusive and, therefore, are uncomfortable to insert, wear and remove, with low patient satisfaction and compliance. They are also relatively expensive, and therefore designed to be reusable. Various pessary devices have been designed to treat prolapse in women, for example, U.S. Pat. No. 6,189,535; U.S. Pat. No. 6,158,435; U.S. Pat. No. 5,894,842; U.S. Pat. No. 5,771,899; U.S. Pat. No. 5,611,768; U.S. Pat. No. 4,823,814; and GB 19124034, the disclosures of which are herein incorporated by reference.
An example of how to overcome some of the above limitations in the prior art would be to provide a flexible pessary which assumes a low profile for insertion and removal, but which assumes a larger profile while treating pelvic organ prolapse.
Another example of how to overcome some of the above limitations in the prior art would be to provide a pessary that does not apply direct pressure to the urethra, thereby restricting a woman's ordinary urinary function.